Auto: s7-c4 — deadband / on-change with thresholds

Closes #297

src/ZB.MOM.WW.OtOpcUa.Driver.S7/S7DriverFactoryExtensions.cs

@@ -90,7 +90,9 @@ public static class S7DriverFactoryExtensions
             Writable: t.Writable ?? true,
             StringLength: t.StringLength ?? 254,
             WriteIdempotent: t.WriteIdempotent ?? false,
-            ScanGroup: string.IsNullOrWhiteSpace(t.ScanGroup) ? null : t.ScanGroup);
+            ScanGroup: string.IsNullOrWhiteSpace(t.ScanGroup) ? null : t.ScanGroup,
+            DeadbandAbsolute: t.DeadbandAbsolute,
+            DeadbandPercent: t.DeadbandPercent);
 
     private static T ParseEnum<T>(string? raw, string driverInstanceId, string field,
         string? tagName = null, T? fallback = null) where T : struct, Enum
@@ -167,6 +169,23 @@ public static class S7DriverFactoryExtensions
         ///     default publishing interval).
         /// </summary>
         public string? ScanGroup { get; init; }
+
+        /// <summary>
+        ///     PR-S7-C4 — optional absolute deadband threshold. Numeric tags whose
+        ///     <c>|new - prev|</c> is strictly less than this value are suppressed at
+        ///     the driver layer before <c>OnDataChange</c> fires. Ignored for non-numeric
+        ///     types. NaN / ±Infinity samples bypass the filter and always publish.
+        /// </summary>
+        public double? DeadbandAbsolute { get; init; }
+
+        /// <summary>
+        ///     PR-S7-C4 — optional percent deadband (0..100). Numeric tags whose
+        ///     <c>|new - prev|</c> is strictly less than <c>|prev| * pct / 100</c> are
+        ///     suppressed. Falls back to <see cref="DeadbandAbsolute"/> when
+        ///     <c>|prev| &lt; 1e-6</c> (near-zero baseline rule). When both deadbands are
+        ///     set the filters are OR'd — publish if EITHER threshold triggers.
+        /// </summary>
+        public double? DeadbandPercent { get; init; }
     }
 
     internal sealed class S7ProbeDto